A wheel drive such as used in construction equipment normally comprises a hydraulic motor that is mounted in the hub, and a planetary-gear transmission connected between this motor and the body of the motor vehicle. Normally a relatively long axial spacing must be provided between the motor and the transmission.
Such an arrangement is also associated with a brake that must engage directly on the wheel hub or on an element jointly rotatable therewith. Thus the brake for such an arrangement must be able to stop the vehicle by exerting considerable force. Such a brake is normally a relatively bulky and heavy-duty unit.
Another disadvantage of these units is that when the vehicle is operated at road speeds, either when driving itself or when being towed, the motors are operated pump-fashion at high speed. Even when the inputs and outputs of the motors are connected together to reduce resistance, this type of operation results in considerable strain on the motors and consequently greatly decreases their service life.